Doesn't autofill defeat security? (newbie..I have only setup one pw on Mac and trying Android)

Thanks for your comments FrankBreech. A malicious actor with full access to a device could circumvent almost any precautions with enough time and effort.

There are other situations where your device might be freely available but you still want to limit access to your accounts. For instance you may not want a young child to make purchases on your tablet! Turning Lock on exit or Automatically lock on from Settings > Security will help ensure your account password or biometrics are required before filling.

I also wanted to add our guide on what to do if your device is lost and it has your 1Password data on it:
* If your device was lost or stolen, and it has your 1Password data on it